There's also a liability factor. My old shop had a relative (cousin / nephew) that wound up strung out on something. When he got wind he was going to be canned, he took one of the company vans home one night, and never showed for work in the morning.
They found the van (empty, but otherwise intact) by his girlfriend's apartment building. And of course, sharing a last name, all of the equipment being marked didn't make it obvious.
